Overview

The coin press is a rather advanced building. It is mainly used by advanced tribes, or traders who have managed to set up a standard currency with the entire server, without anyone else making their own coin press, which is an extremely uncommon occurrence.
You can use a coin press to make gold coins. If a coin press is used with a shop, you can have a pretty effective trading system, but the hard part is getting the server to accept gold coins, as the only real use for them is to make people, which are completely useless to most players, unless they like pointless decorations, so you would need to get a large chunk of the server to start trading with them before the general public start doing likewise.
You can also make a floating island using coin presses, as the coin press has an anchored block. The way to use a coin cress is to click on the small square block under the coin presser and combining it with refined gold.